Call back method

ABSTRACT

Communication system comprising one or more exchanges and a number of terminals (telephone sets, facsimile apparatuses, etc.) which each through one of the mentioned exchanges is able to communicate with at least one of the other terminals whereby a) the user of a calling terminal calls the number of its own exchange, transmits signals indicating that the terminal has to be called back by the exchange after which the connection is cut off, b) thereafter the exchange establishes a connection with the calling terminal, c) the user of the terminal transmits the number of a desired other terminal to the exchange, d) the exchange thereafter establishes the connection with the desired terminal, whereby at least the calling terminals can be connected partly through wireless communication paths with their own exchange and to comprise a buffer in which the number of the desired other terminal can be stored, and comprise a circuit which, after said number is keyed in by the user and is stored in the said buffer, performs the above-mentioned steps a) instead of the user, waits until the exchange reports again, retrieves the number from said buffer and transmits this number instead of the user to the exchange which will perform thereafter step d).

FIELD OF THE INVENTION

The invention relates to a call back method in a communication systemcomprising one or more exchanges and a number of terminals (telephonesets, facsimile apparatuses, etc.) each of which being able tocommunicate through at least one of said exchanges with at least one ofsaid other terminals, which method includes the performance of thefollowing steps:

establishing a connection with a predetermined exchange

transmitting signals to the exchange indicating the number of thecalling terminal, the number of the called terminal and the fact thatthe calling terminal has to be called back,

breaking the connection and wait for the exchange to establish theconnection.

BACKGROUND OF THE INVENTION

Such a method is described in WO9201350. Various embodiments of callback methods are described in this publication. The disadvantages willbe described in the following. In general these prior art methodsrequire significant effects from the user who has to be active during atleast the first two of the above-indicated steps.

Such a system, in which use is made of the so-called call backprocedure, is known as such for wire-bounded communication systems. Theadvantage of such systems is in many cases that the communication costsof the actual communication between the calling terminal and the desiredterminal are calculated on the basis of date which will become availablefrom the exchange which was involved in establishing the connection.

In general a number of exchanges are involved into establishing aconnection, certainly if we are talking about trunk or internationalcommunication traffic. In general thereby the costs will be calculatedby the first exchange in the series onto which the calling terminal isconnected. That can be an exchange which calculates according to arelatively high tariff.

By making use of a call back procedure any arbitrary exchange anywherein the world which preferably calculates according to a relatively lowtariff, can be used for establishing the actual connection. Althoughsometimes contact has to be made with the call back exchange accordingto a relatively high tariff for a short while the timespan of thisconnection is very restricted. However, in many cases duringestablishing the connection use will be made only of signalling of whichthe costs are much lower or even nil.

A practical disadvantage of such a call back procedure is that to startwith the user has to call the number of the call back exchange, has towait thereafter until the call back exchange reports back and has to keyin the number of the desired terminal thereafter. This procedure is verylaborious. If automatic number callers are used this will lead topractical or sometimes even insurmountable problems.

It is sometimes possible by means of a predefined number translation toorder the exchange directly to call a restricted number of predefinednumbers. This, however, has the disadvantages that an extra manipulation(taking up the receiver) is still necessary, the number of items isrestricted and always an appeal should be made to the memory of thecaller to establish the correct connection.

In the mean time automatic call back diallers are developed forterminals in wire-bounded systems by means of which the above describedmanipulations can be automated. For wireless connections from a mobileterminal (mobile telephone, fax, modem, etc.) no corresponding solutionsare known.

OBJECT OF THE INVENTION

The purpose of the invention is now to indicate in which manner thesystem can be modified such that the user of a mobile terminal (amongwhich are not comprised the terminals which in many home exchanges orcompany exchanges cooperate in a wireless manner with a fixed centralstation) is not confronted any more with the above-described laboriousprocedure, but, as in a wire-bounded system, only has to key in thenumber of the desired terminal to get a connection with said desiredterminal.

SUMMARY OF THE INVENTION

In correspondence with the invention the system of the type as describedin the first paragraph is characterized in that at least the callingterminals can be connected partly through wireless communication pathswith their own exchange and do comprise a buffer in which the number ofthe desired other terminal can be stored, and comprise a circuit which,after said number is keyed in by the user and is stored in the saidbuffer,

performs the above-mentioned step a) instead of the user,

waits until the exchange reports again, retrieves the number from saidbuffer and transmits this number instead of the user to the exchangewhich will perform thereafter step d).

The added circuit according to the invention attends therefore to such alarge part of the procedure that the only thing the user has to do iskey in the number of the desired terminal.

According to a further development of the invention the circuit isfurthermore capable to suppress the ringing signal which otherwise wouldsound when the connection is made by the exchange to the callingterminal.

Therewith the calling terminal acts in relation to the user as aconventional terminal and the user will not notice that a call backprocedure is applied.

The invention not only relates to a whole system as above described butalso relates to separate terminals. According to the invention themobile terminal is characterized in that the terminal comprises a bufferin which the number of the desired other terminal is stored andcomprises a circuit which, after said number is keyed in by the user andis stored in the buffer,

establishes the connection with the exchange,

reports as calling terminal,

after the connection is cut off waits until the exchange has establishedthe connection again and retrieves the number from said buffer andtransmits it to the exchange.

In many of the known mobile terminals use is made of a detachable moduleknown as the SIM module or a therewith corresponding detachable unit inwhich a part of the electronic circuits (amongst others destined foridentification purposes) is housed. It is found that the circuit, whichaccording to the invention has to be added to the terminal to performthe above identified functions can be housed in this SIM module. Thisprovides the possibility to adapt existing mobile terminals in a simplemanner such that they can be applied in a communication system accordingto the invention.

In relation to the generally higher tariffs which apply for mobilecommunication over a wireless network (for instance GSM, Inmarsat, etc.)a suitable choice of the “call back exchange” can lead to significantfinancial advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a communication system according to the state of theart.

FIG. 2 illustrates a communication system in which the characterizingfeatures according to the invention are applied.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a terminal 10, for instance a mobile telephone, whichthrough a wireless communication path 12 is able to establishes aconnection with a suitable exchange 30. Through said exchange 30 theterminal 10 is able to establish a connection with another terminal, forinstance through the wireless path 14 with a mobile telephone 20 orthrough a wire-bounded network 24 with a wire-bounded terminal 22.

In case the terminal 10 for instance wants to establish a connectionwith the terminal 20, then the terminal 10 will transmit a signalthrough the wireless path 12 to the exchange 30. Thereafter the numberof the desired terminal 20 will be transmitted to the exchange 30whereafter the exchange will take care that through communication path14 the terminal 20 is called. As soon as the terminal 20 reports back,the connection from terminal 10 to terminal 20 through the exchange 30is established. In a similar manner the terminal 10 is able to establisha connection with the wire-bounded terminal 22.

In this prior art procedure the costs of the communication connectionbetween the terminal 10 and the terminal 20 respectively 22 arecalculated on the basis of the standards handled by the exchange 30.

FIG. 2 illustrates a configuration whereby besides the terminals 10 and20 and the exchange 30 an other exchange 40 is involved. The terminals10 and 20 are for instance embodied again as mobile telephones and areable to establish a connection with the exchange 30 respectively throughthe wireless communication path 12 and the wireless communication path14. The wire-bounded apparatus 22 is connected to the exchange 30through the network 24. The system comprises furthermore an otherexchange 40 which through a communication path 16 is able to get intocommunication with the exchange 30. The communication path 16 will ingeneral run through cables. In the communication path 16 in general oneor more further exchanges will play a role, however, only for performingswitch through functions and therefore these exchanges are within thescope of the invention of less relevance. It is only made clear that theexchanges 30 and 40 may have in a geographical sense a large mutualdistance.

It is now assumed that the terminal 10 has no subscriber relation withthe exchange 30 but has a subscriber relation with the exchange 40.However, at the moment the terminal 10 is situated within the influencearea of the exchange 30. As soon as the mobile apparatus 10 indicates,by transmitting the number of the exchange 40, that he wants to make aconnection with another terminal then said number will be received bythe exchange 30 and will be transmitted to the exchange 40. The exchange40 recognizes the identity of the calling terminal 10 (for instance bymeans of the Calling Line Identification) whereafter the furtherconnection is prohibited or an eventual established connection is cutoff through the calling terminal or through the exchange. Thereafter theexchange 40 will establish a connection with the terminal 10, receivesfrom the terminal 10 the number of the desired subscriber such as themobile terminal 20 or the wire-bound apparatus 22 and establishes theconnection with said terminal 20 respectively the apparatus 22. Therebyit is not necessary that the same communication routes will be used. Itis very well conceivable that dependent on the available free channelsthe final connection runs along other paths.

In this configuration according to FIG. 2 in fact the exchange 40 willprovide the data on the basis of which the costs of the communicationconnection between the terminals 10 and 20 will be calculated. In casethe exchange 40 uses a lower tariff than the exchange 30, then thesubscriber 10 who has to pay for the connection has the benefit.

To perform the whole procedure such that the user of the terminal 10 isnot aware of the manner in which the connection is established, it isnecessary to add a buffer 18 to the terminal 10 in which buffer thenumber of the called subscriber 20 (or 22) is stored as well as thenumber of the exchange 40 is stored and furthermore an electroniccircuit 19 which reacts on the return call of the exchange 40 byaccepting this return call and by transmitting the number of theterminal 20 or 22 which is stored in the buffer 18. The user of theterminal 10 is not aware of this and keeps waiting until the calledterminal 20 (or 22) reports itself. In fact the user of terminal 10 getsthe feeling that the connection is made in the same manner as in theconfiguration according to FIG. 1. The essential difference, however, isthat the costs of the established connection in case of theconfiguration of FIG. 2 can be significantly lower. The costs aredependent on the tariff according to which the calculations are made inthe exchange 40.

What is claimed is:
 1. A call-back system, comprising: a first wirelessterminal, and a second wireless terminal; a first exchange in wirelesscontact with the first and second terminals; a wire-bounded terminalconnected to the first exchange through a wired communication network; asecond exchange in communication with the first exchange, the secondexchange including a call-authorization function, using a call-back callto the first terminal, to authorize calls from the first wirelessterminal to another terminal via the first exchange while bypassing thesecond exchange; a buffer located within the first terminal, the bufferconfigured for storing the number of called terminals; and an electroniccircuit within the first terminal, the electronic circuit for acceptinga call-back call-authorization call originated at the second exchange,wherein, the first terminal has no subscriber relation with the firstexchange and has a subscriber relation with the second exchange, withthe first terminal being situated within an influence area of the firstexchange, the first terminal transmits a number to make a connectionwith another terminal, the number is received by the first exchange andtransmitted by the first exchange to the second exchange, the firstterminal also storing the number in the buffer, upon receiving thenumber, the second exchange recognizes the first terminal and decides toauthorize the connection of the first terminal to the another terminalto establish a call via the first exchange while bypassing the secondexchange and makes the call-back call to the first terminal, theelectronic circuit of the first terminal accepting the call-back callwith the call-authorization from the second exchange and makes theconnection to the another terminal via the first exchange, the firstterminal making the connection using the number of the another terminalstored in the buffer.
 2. The system of claim 1, wherein the secondexchange makes the decision to authorize the connection of the firstterminal to the another terminal, via the first exchange while bypassingthe second exchange, based on a comparison of costs for the firstexchange to route the call and costs for the second exchange to routethe call.
 3. The system of claim 1, wherein the another terminal is thesecond wireless terminal.
 4. The system of claim 1, wherein the anotherterminal is the wire-bounded terminal.
 5. The system of claim 1, whereinthe buffer is configured to store a number of the second exchange. 6.The system of claim 1, wherein the electronic circuit is housed in a SIMmodule.
 7. A call-back terminal, comprising: a first wireless terminalin wireless contact with a first exchange and, via the first exchange,in communication with a second exchange, the second exchange including acall-back call-authorization function to authorize calls from the firstwireless terminal to another terminal via the first exchange; a bufferlocated within the first terminal and configured for storing the numberof a called terminal; and an electronic circuit within the firstterminal configured for accepting a call-back call-authorization fromthe second exchange, wherein, the first terminal has no subscriberrelation with the first exchange and has a subscriber relation with thesecond exchange, the first terminal transmits a number to make aconnection with another terminal, the number is received by the secondexchange via the first exchange, the number is also stored in thebuffer, upon receiving the number, the second exchange recognizes thefirst terminal and decides to authorize the connection of the firstterminal to the another terminal to establish a call via the firstexchange and makes a call-back call-authorization call to the firstterminal, the electronic circuit of the first terminal accepting thecall-back call-authorization from the second exchange and thereaftermakes the connection to the another terminal to establish the call, thefirst terminal making the connection using the number of the anotherterminal stored in the buffer via the first exchange and bypassing thesecond exchange.
 8. A call-back method in a communication systemcomprising at least one exchange and at least one terminal, the oneterminal provided with a buffer circuit for storing a called terminalnumber, the one terminal provided with an electronic circuit forreceiving a call-back call from an exchange, comprising the steps of: auser entering into the one terminal a number to make a wireless call toanother terminal, the entry of the number storing the number in thebuffer; the electronic circuit establishing a connection at least partlythrough wireless paths with a predetermined exchange; the electroniccircuit transmitting signals to the predetermined exchange indicatingthat the one terminal has to be called back; the electronic circuitbreaking the connection and waiting for the predetermined exchange tocall back; the one terminal receiving a call-back call from thepredetermined exchange and, upon a call-back connection beingestablished, retrieving the stored number from the buffer andtransmitting the number to the predetermined exchange; the predeterminedexchange accepting the transmitted number from the one terminal andestablishing a completed connection between the one terminal and anotherterminal; upon establishing the completed connection, switching controlof the terminal to the user.
 9. A terminal adapted to carry out thecall-back method according to claim 8, characterized in that theterminal comprises the buffer circuit and the electronic circuit. 10.Terminal according to claim 9, characterized in that the electroniccircuit is housed in a SIM module.